The invention relates to a novel device for taking samples, especially fluid and more particularly liquid, on a pipeline.
During many manufacturing or synthesizing processes in various industries, especially chemistry, petrochemistry, pharmaceuticals and agri-foodstuffs, it proves necessary to conduct one or more checks on the quality of the product being manufactured or prepared in the course of the various steps of the process in question, the purpose of this being, in particular, to arrive at a product meeting the required quality standards and thereby to avoid rejects by exerting an influence, as a function of the analyses carried out, on the parameters and the conditions implemented during the said process.
To this effect, conventional cocks are usually installed on the pipelines for transferring the products and make it possible to collect the said products manually in order to conduct an analysis of them. Apart from the fact that, with such a cock, the operator comes into direct contact with the fluid to be analysed or its vapours, which may be toxic, the quantity of liquid sampled is entirely arbitrary and, moreover, the sealing of this type of cock is often insufficient for a large number of applications.
There are flap-type or pintle-type sampling systems which are mounted on a branch of the main pipeline and which then make it possible to fill a bottle. The sealing member of the cock consists of a flap, a pintle or a cylinder; opening takes place either directly in the fluid stream or in the body of the cock by means of a wheel which releases the sealing member from its seat and allows the liquid to flow into the bottle.
This system has some disadvantages. In fact, it is necessary to have good sealing relative to the passage of the control spindle (gland) and the seat. Now this sealing is relatively difficult to obtain with regard to chemically aggressive and/or heavily laden fluids. Moreover, it deteriorates more and more in proportion to the increase in the number of operations. Finally, the bottle is subjected to the same pressure as that of the main pipe.
Finally, a device employing a system of needles, which consists of a valve, of a needle fastening and of a protective sleeve, is also provided. Two needles are provided, one for sampling and the other for escape. Such a system is mounted on the pipe by means of the connections of the valve. However, although this device makes it possible to sample a specific quantity of product to be analysed, nevertheless the said product can only be extremely clean and of very low viscosity, in view of the use of needles, the outflow orifice of which is very narrow, thus drastically reducing its applications. Furthermore, it is necessary to use a bottle equipped with a diaphragm adapted to each product, in order to ensure good sealing.